mysqldump out of memory on large DB

[Christian Mueller]

Hi,

first i wanna state that i already learned a lot from this forum, thank you guys for helping others out.

so heres my setup and my problem.

i have a 32bit Debian Server with mysql-server 5.0.51a.
When i try to mysqldump a large Database or large Table (6-10GB), mysql-server seems to crash.
(its a myisam database with key_buffer_size set to 384M, as set in the my-huge.cnf example)

[mysqldump] section in my.conf contains:
quick
quote-names
max_allowed_packet = 16M

I found some threads in this forum and others, where people complained about the same problem, and were told to use the --quick parameter for mysqldump, but the mysqldump manpage says it is on by default.

1.) Just for clarification: IS it really on? and why is mysql crashing if the dump is not buffered, but instead written to file directly?

2.) another one is being told to use --skip-opt --quick, but wouldn't it make more sense to use --extended-insert, too, because it should shrink the output file?

3.) could there be anything else i am missing or i could try? and can it be the memory limit from the 32bit system (i am pretty sure the dumping did work some time ago, not sure about the db size though)



from syslog (just in case anyone can draw conclusions from it):
kernel: mysqld invoked oom-killer: gfp_mask=0x44d0, order=2, oomkilladj=0
kernel: Pid: 14717, comm: mysqld Not tainted 2.6.29-xs5.5.0.14 #1
kernel: Call Trace:
kernel: [<c0153ed8>] oom_kill_process+0x71/0x1c5
kernel: [<c01544e3>] __out_of_memory+0x108/0x11b
kernel: [<c0154550>] out_of_memory+0x5a/0x7c
kernel: [<c01569c8>] __alloc_pages_internal+0x2d6/0x385
kernel: [<c0156aa4>] __get_free_pages+0x11/0x1e
kernel: [<c0220f27>] __alloc_skb+0x49/0xf3
kernel: [<c021d7cc>] sock_alloc_send_skb+0x83/0x1ab
kernel: [<c0104e32>] check_events+0x8/0xe
kernel: [<c0104d9b>] xen_restore_fl_direct_end+0x0/0x1
kernel: [<c026c1fe>] unix_stream_sendmsg+0x177/0x2e9
kernel: [<c021a8ad>] sock_aio_write+0xe8/0xf5
kernel: [<c0176640>] do_sync_write+0xc0/0x107
kernel: [<c012f90d>] do_tkill+0xc6/0xdb
kernel: [<c0135cf2>] autoremove_wake_function+0x0/0x2d
kernel: [<c0104e32>] check_events+0x8/0xe
kernel: [<c012a567>] irq_exit+0x40/0x62
kernel: [<c0176e0d>] vfs_write+0x95/0xf7
kernel: [<c0176f07>] sys_write+0x3c/0x63
kernel: [<c0106edf>] sysenter_do_call+0x12/0x33